Low rate of seroconversion analyzing QuantiFERON TB-gold testing in patients with psoriasis and hidradenitis suppurativa taking biologic therapy at an academic center in New York City

Ohio (TB burden 1.3/ 100,000), only 1 patient (0.4%) seroconverted. 3 Studies conducted in countries with higher-TB prevalence reported higher seroconversion rates. A retrospective study of psoriasis patients taking TNFI’s in Taipei, Taiwan (TB burden 30/100,000), reported 7.3% of patients seroconverting. 4 In a retrospective study psoriasis patients taking TNFI’s in Ankara, Turkey (TB burden 16/100,000), 5.2% seroconverted. 5

To the Editor: Current guidelines advise tuberculosis (TB) baseline screening before initiating biologic medications, due to risk of latent tuberculosis infection reactivation, with varying recommendations on repeat screening.Studies analyzing screening in US cities with high TB rates are lacking.We aimed to stratify utility of serial QuantiFERON TB-gold (QFT) testing in patients with psoriasis or hidradenitis taking biologic treatment for hidradenitis suppurativa in New York City (NYC), which has high TB burden.
Weill Cornell Medical Center's EPIC database was queried March 23, 2011 to July 21, 2023 for psoriasis or patients with hidradenitis suppurativa with ages $18 years treated with a biologic, with $2 QFT test results, with $1 prior to treatment.Wilcoxon ranksum tests evaluated mean ages and number of risk factors between seroconverters and nonseroconverters (P \ .05).Receiver operating characteristic analysis with Youden index identified optimal age cutoff for seroconversion risk.
A total of 356 patients were included (Table I).Overall, 71.6% of patients resided in NYC, (TB burden 6.1 cases/100,000 people), and 90.1% lived   II).All 3 true seroconverters were treated for latent tuberculosis infection and none developed active TB.We found a low rate of seroconversion (\1%) in patient taking biologics for dermatologic conditions in NYC, which has relatively high TB prevalence.Seroconversion rates in our study were surprisingly similar to studies conducted in cities with lower TB burdens.A retrospective study of 570 psoriasis patients taking TNF alpha inhibitors (TNFIs) in Iowa City, Iowa (TB burden 1.5/100,000), reported only 1 (0.2%) true seroconverter. 2 In another singlecenter retrospective study of 265 psoriasis patients on TNFI's in Cleveland, Ohio (TB burden 1.3/ 100,000), only 1 patient (0.4%) seroconverted. 3 Studies conducted in countries with higher-TB prevalence reported higher seroconversion rates.A retrospective study of psoriasis patients taking TNFI's in Taipei, Taiwan (TB burden 30/100,000), reported 7.3% of patients seroconverting. 4In a retrospective study psoriasis patients taking TNFI's in Ankara, Turkey (TB burden 16/100,000), 5.2% seroconverted. 5imitations include small sample size, a singlecenter setting, and a retrospective design.
In sum, we found a low rate of seroconversion (\1%) in patient taking biologics for psoriasis and hidradenitis suppurativa in NYC, which has relatively high TB burden.True seroconverters were older, on average, than other subjects.We recommend a single baseline QFT test and annual testing only for patients age $66 taking biologics for dermatologic conditions, which may reduce costs and avoid unnecessary treatments.
Apostolos Katsiaunis, BS, a Jade Conway, BA, b Debra D'Angelo, MS, c and Shari R. Lipner, MD, PhD d From the Tufts University School of Medicine, Boston, Massachusetts a ; School of Medicine, New York Medical College, Valhalla, New York b ; Division of Biostatistics, Department of Population Health Sciences, Weill Cornell Medicine, New York, New York c ; and Department of Dermatology, Weill Cornell Medicine, New York, New York.d

Table I .
Patient demographics, treatment details, and QuantiFERON TB-gold testing outcomes

Table I .
Cont'd

Table II .
Demographics and outcomes of patients who seroconverted Low zip code tuberculosis risk level indicates under 10 active tuberculosis cases per 100,000 people.